A surgical microscope used for, for example, neurosurgery is supported with a suspension arm at a front end of a support arm of a stand apparatus and is used in this state. To freely change an observation direction, the surgical microscope is supported with the suspension arm so that the surgical microscope is freely movable in front-rear and left-right directions.
More precisely, as disclosed in Japanese Patent Publication No. 2825721, the suspension arm itself consists of a small parallel linkage so that the suspension arm itself deforms to turn (incline) the surgical microscope supported at a lower end of the suspension arm in the left-right direction. The surgical microscope is supported at the lower end of the suspension arm with a shaft so that the surgical microscope freely turns in the front-rear direction around a horizontal rotation axis. Accordingly, in terms of the viewing direction of an observer, the surgical microscope freely turns in the left-right and front-rear directions to optionally change an observation direction.